Paleotemperature Adjustments for Obsidian Hydration Dating

Summary

This is an abstract from the "Advances in Obsidian Studies of the Old and New Worlds" session, at the 84th annual meeting of the Society for American Archaeology.

Obsidian hydration dating (OHD) is a method for estimating age of an obsidian artifact based on time-dependent absorption of water. The process is temperature-sensitive, and its application to archaeological dating currently requires assuming that current temperature parameters are a reasonable approximation to ancient temperatures. This is generally valid for ages in the Holocene, but temperature proxy data show significant shifts in ancient temperatures relative to the present, especially for ages before approximately 12-13Kya. For these ages, the prevailing temperatures were significantly cooler than today, and ages computed assuming current conditions will be too young. We describe a simple numerical method for correcting OHD ages for long-term changes in climatic temperature regimes, based on published temperature proxy data. The method is based on reading hydration rims by optical microscopy; however, since the method applies to the ages and not to the measurements themselves, it will also work for other measurement methods: secondary ion mass spectrometry (SIMS); FTIR or IRPAS spectrometry; manometry; or SIMS/SS. We present calibration curves relating paleo-corrected to uncorrected ages.

This Resource is Part of the Following Collections

• Society for American Archaeology 84th Annual Meeting, Albuquerque, NM (2019)   •
• Advances in Obsidian Studies of the Old and New Worlds

Keywords

Record Identifiers

Abstract Id(s): 23781